UPS MD-11 Crashes on Takeoff

[Hall]

That's the reason that the lower tier services are offered.

Sadly, what I described rarely happens anymore. Well, they may still move it early but nowadays, they'll just let pieces sit, then deliver it when it was initially scheduled for delivery vs delivering it early. Customers can't complain 'cause they're getting what they paid for, but it still seems inefficient to sit on things.

The same is true for passenger flights, although you rarely get one with only a handful of passengers these days.

I used to hear about this happening a lot but nowadays, you'll hear that airlines just cancel the flight vs only take 1, 10, etc passengers vs 75-100% full. Odd thing is though, and just like cargo, that plane still needs to be somewhere else for subsequent flights.

 

[fdcg27]

Sadly, what I described rarely happens anymore. Well, they may still move it early but nowadays, they'll just let pieces sit, then deliver it when it was initially scheduled for delivery vs delivering it early. Customers can't complain 'cause they're getting what they paid for, but it still seems inefficient to sit on things.

I used to hear about this happening a lot but nowadays, you'll hear that airlines just cancel the flight vs only take 1, 10, etc passengers vs 75-100% full. Odd thing is though, and just like cargo, that plane still needs to be somewhere else for subsequent flights.

Well, when the package flies and when it reaches the consignee may not coincide, but it makes perfect sense for the package to be delivered on the schedule paid for, otherwise every shipper would just use third day air.
With passenger airlines I'd doubt that flights are cancelled last minute due to low loads. A few weeks or even days ahead, sure, the carrier can plan around that. Same day? Probably not.
Airlines that fly a bunch of less than daily nonstops, like Allegiant, maybe.

 

[MolaKule]

Back on topic. Juan Browne gives a third update and analysis of this crash in which he also discusses the possibility of a Turbine disk fracture/malfunction at 9:30. See also my post #101 in this thread:



American Flight 383 NTSB report:

"...The uncontained engine failure resulted from a high-pressure turbine (HPT) stage 2 disk rupture. The HPT stage 2 disk initially separated into two fragments. One fragment penetrated through the inboard section of the right wing, severed the main engine fuel feed line, breached the fuel tank, traveled up and over the fuselage, and landed about 2,935 ft away. The other fragment exited outboard of the right engine, impacting the runway and fracturing into three pieces..."

https://www.ntsb.gov/investigations/AccidentReports/Reports/aar1801.pdf?pubDate=20251108

 

[FowVay]

Here's a manual diagram of the engine mounts. The fwd mount is attached to the fan frame (not fan case) and the after mount is attached to the turbine rear frame. If the pylon mounts were still attached to the engine mounts then it's obviously a pylon failure.

The photo of the engine laying on the ground is very grainy but I can distinctly see the HPT housing and it looks intact from this specific view. I can see a fan blade failure but I do not subscribe to a turbine blade failure.

 

[Faawrenchbndr]

I’m rather sure the fan was the failure point.
It explains the issues with #3 and FOD, creating a compressor stall. A core shift or seizure could explain the forces that led to a pylon separation from the wing. It also wouldn’t surprise me if they found corrosion or a failed previous repair.

 

[MolaKule]

...Here's a manual diagram of the engine mounts. The fwd mount is attached to the fan f
The photo of the engine laying on the ground is very grainy but I can distinctly see the HPT housing and it looks intact from this specific view. I can see a fan blade failure but I do not subscribe to a turbine blade failure...

Thanks, FowVay, good description, but I am postulating and subscribing to a turbine disk failure.

"The most likely time for an uncontained rotor failure to occur is during take-off, when the engine is under highest stress. Using the industry-accepted standards for the percentage of engine failures occurring within each flight phase, the following probabilities are assumed:

Take-off before V1 35%
V1 to first power reduction 20%
Climb 22%
Cruise 14%
Descent 3%
Approach 2%
Landing/Reverse 4%..."

From, FAA AC-20-128A

with a rotation speed of 11,500 rpm and an operating temperature of 1400F, these turbine components are under very high centrifugal and temperature stresses.

https://www.seitzman.gatech.edu/classes/ae4803/turbine_stresses.pdf

NASA Study with many illustrations:

https://ntrs.nasa.gov/api/citations/19760019113/downloads/19760019113.pdf

 

[FowVay]

I still don't believe it has anything to do with the turbine. Here is what a turbine disk failure looks like - it's not going to rip an engine from it's pylon. This is a stage 2 HPT disk from the no. 1 engine. This picture shows the disk tearing through the no. 2 engine of a B767. Until we can see a good view of the engine it's difficult to say for certain but the HPT on the D1F appears to be intact and certainly not destroyed enough to rip the engine from the aircraft. The HPT on these engines consists of two stages and there really isn't a whole lot of mass when compared to the stage 1 LPC.

And just for those who aren't aware, these engines are all essentially the same. There are minor differences and thrust rating differences and even some fan diameter differences but the propulsors are virtually identical across the product line. What changes between aircraft is the pylon design. All CF6 engines use the same engine mount but the pylon mounts are unique to each airframe.

CF6-80C2 B8F - Boeing airframe
CF6-80C2 D1F - McDonnell Douglas airframe
CF6-80C2 E1F (A1 for older models) - Airbus airframe
CF6-80C2 K1F - Kawasaki airframe (Japanese military)

The major differences with these engines is how the pylon holds the engine to the wing. Ducting will vary depening on which side of the aircraft the engine hangs but all other things are essentially equal. This is the second MD-11 I've heard of that has lost a no. 1 engine so there is quite possibly an issue with the design and engineering of these pylons.

 

[y_p_w]

That's the downside of freight service, especially with services like those from UPS, Fedex, DHL, etc. Those planes are flying from point A to point B whether they're at 10% capacity or 100% capacity. Years ago, if you shipped something using 2-day or 3-day service, you could often get things in (1) day if "the planes weren't full".

Really? I remember buying something that was shipped 3rd day FedEx. It came to me from the Central Valley and was held at the FedEx facility in Emeryville, California. Never got on a plane and I could track the location. But they refused to release it to me until the 3rd day.

 

[y_p_w]

Sadly, what I described rarely happens anymore. Well, they may still move it early but nowadays, they'll just let pieces sit, then deliver it when it was initially scheduled for delivery vs delivering it early. Customers can't complain 'cause they're getting what they paid for, but it still seems inefficient to sit on things.

I used to hear about this happening a lot but nowadays, you'll hear that airlines just cancel the flight vs only take 1, 10, etc passengers vs 75-100% full. Odd thing is though, and just like cargo, that plane still needs to be somewhere else for subsequent flights.

Yeah - I mentioned that I got a 3rd day that never got on a plane and was shipped from less than 120 miles away. 3rd day was my cheapest shipping option. I suppose if someone ordered the same thing from the other side of the country, it would have gotten on a plane at some point. Maybe even overnight but held for delivery/pickup.

 

[Exhaustgases]

Curious of how many air carriers have their maintenance done in other country's? I remember reading something about it being a huge cost savings for them, in some publication. I would be guessing, but I feel the best and most qualified for jet engine work would be Kalitta air. Connie is a smart guy.

 

[MrJayhawk]

FAA has issued a formal no fly directive.

https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID188588539020251108211920.0001

 

[Nuclear_42]

Curious of how many air carriers have their maintenance done in other country's? I remember reading something about it being a huge cost savings for them, in some publication. I would be guessing, but I feel the best and most qualified for jet engine work would be Kalitta air. Connie is a smart guy.

All Big 3 passenger airlines sent work overseas. Pretty much whole industry does it. El Salvador is very popular.

 

[Faawrenchbndr]

Curious of how many air carriers have their maintenance done in other country's? I remember reading something about it being a huge cost savings for them, in some publication. I would be guessing, but I feel the best and most qualified for jet engine work would be Kalitta air. Connie is a smart guy

Kalitta is a wonderful guy. The whole family is. But it’s a horrible place to work. There are some great people there but it’s a near hostile environment

Last numbers I saw on non US maintenance and repair work was about 35-50%. Some of the smaller airlines are closer to 75%……like Spirit

I did leave the industry right at three years ago. I really haven’t kept up with the numbers. I doubt the current percentage is any less.

 

[Dave Hess]

I remember the DC3 bringing pallets to our usaf base in Alaska....They were tied down....and not very secure either....

What year was that ?

 

[Dave Hess]

All Big 3 passenger airlines sent work overseas. Pretty much whole industry does it. El Salvador is very popular.

I’ve heard that before.

Do these overseas companies have qualified staff to work on these aircraft ?

Here in the USA lots of A&P mechanics were previously in the military working on various aircraft / helicopters so they had very good training from the very beginning.

 

[Faawrenchbndr]

I’ve heard that before.

Do these overseas companies have qualified staff to work on these aircraft ?

Here in the USA lots of A&P mechanics were previously in the military working on various aircraft / helicopters so they had very good training from the very beginning.

Yes, they have qualified mechanics and inspectors

The scary part is this. Usually what happens in a lot of these facilities is you’ll have one ANP mechanic watching over six or eight maybe 10 individuals. These individual individuals or workers are experienced in the job jobs. They are doing, but they are not FAA licensed A&P holders.

Then, of course, quite a few jobs have a FAA A&P with IA certification, they sign off on quite a bit of work, following the A&P mechanics sign off.

I ran into this with quite a few small repair facilities down in Miami. They didn’t pay very well and one A&P would have 10-12 workers he would be responsible for.

 

[Dave Hess]

When Pan Am went bankrupt and closed down my dad worked for a few small repair facilities in Miami and also saw some very sketchy things.

He quit and retired from the industry. He didn’t need to money but worked at terrible repair facility to stay busy.

Gov will uncover lots of things UPS didn’t know about San Antonio maintenance facility working on their accident MD-11.

 

[rszappa1]

What year was that ?

1973 at Sparrevoh AFS AK.... It was Reeves air Alaska....they still were using DC 3 for cargo....

 

[MolaKule]

Let's close this thread for now. We'll reopen it when new NTSB data becomes available.

 

[MolaKule]

While the NTSB has not released any formal updates, Juan Browne has an update from a few days ago speaking to the pylon separation: